Salmon farming

Modern salmon farming emerged from a Norwegian fishing family's experiment with floating cages, transforming Atlantic salmon from a seasonal wild catch into the world's most efficiently produced animal protein. What started with two brothers and a few hundred fish became an industry producing more salmon than wild fisheries ever could.

The adjacent possible required several elements to align. Norway's coastline offered deep, cold fjords with ideal water temperatures and oxygen levels. Wild Atlantic salmon populations provided broodstock genetics refined by millions of years of evolution. Most critically, the technology of synthetic ropes, styrofoam floats, and rubber tires had made lightweight floating structures possible.

On May 28, 1970, brothers Ove and Sivert Grøntvedt put salmon smolts into a floating open net pen at Hitra, an island off Norway's central coast. Sivert had designed an octagonal cage from wood, styrofoam, and rubber tires—simple, but revolutionary. Unlike closed ponds, the cage allowed ocean currents to flush waste and provide oxygen. Unlike fjord enclosures, cages could be placed in optimal locations and moved if conditions deteriorated.

In 1971, the Grøntvedts harvested the first successful generation of farmed Atlantic salmon. That same year, the Norwegian Fish Farmers Association was established as more families copied the Grøntvedt cage design. Together, pioneers sold 100 tonnes of farmed salmon in 1971. The bonanza had begun.

Path dependence quickly locked in Norwegian dominance. Professor Harald Skjervold at AKVAFORSK applied cattle breeding techniques to salmon, collecting fish from 40 different Norwegian river systems to ensure genetic diversity. The breeding program accelerated growth rates dramatically—salmon accomplished in 14 years and 7 generations what took cattle 60 years. Meanwhile, Thor Mowinckel's A.S. Mowi pioneered egg and smolt production alongside marketing infrastructure.

The cascade transformed global protein production. From 500 tonnes in 1970, Norwegian production reached 8,000 tonnes by 1980, 170,000 tonnes by 1990, and over 500,000 tonnes by the early 2000s. Norway became the world's largest salmon producer, supplying more than half of all farmed Atlantic salmon. The industry spread to Scotland, Chile, Canada, and Tasmania, each adapting the floating cage technology to local conditions.

By 2026, global farmed salmon production exceeds 2.8 million tonnes annually—more than wild salmon catches ever achieved. The floating cage invented by a Norwegian fisherman's ingenuity has become industrial infrastructure, feeding hundreds of millions of people. The Grøntvedt brothers' 1970 experiment domesticated one of the ocean's apex predators.